1. Field of the Invention
The present invention relates to a technology for control display on a screen by a plurality of processing units (tasks and applications), and more particularly to an allocation of the display area.
2. Description of the Related Art
When a plurality of applications display on one screen, a window system, such as X-Window System, has been used. In these window systems, each application displays acquiring the respective window (multi-window).
Japanese Laid-Open Patent Application HEI4-274289 discloses a device which groups windows acquired by each application, and displays or does not display in group units.
Also in accordance with Japanese Patent Laid-Open No. 1-100662, when contents displayed on a plurality of windows are inter-related, these plurality of windows are simultaneously displayed so that the user can easily understand the display contents.
However, with the conventional display based on a multi-window, what application displays on what display area basically depends on the application. Therefore it is possible for an application to display a window which overlaps with the window displayed by another application. When such a problem occurs, the user must change the position of the window which is overlapped by another window in order to view the display of the window, which is troublesome.
In satellite broadcasting TV, where users need not change the positions of windows, different applications must be used to prevent the overlapping display of windows. For such devices, a conventional window system cannot be used.
In accordance with the Japanese Laid-Open Patent Application HEI4-274289, multiple windows specified by an application are grouped so as to improve the operability of each window, but the handling of overlapping of windows depends on the application. In other words, an undesired display of multi-windows is inevitable, and the above mentioned problems are not solved.
In accordance with the Japanese Laid-Open Patent Application HEI1-100662, the handling of overlapping windows also depends on the application, where an undesired display of multi-windows is still inevitable, and the above mentioned problems are not solved.
With the foregoing in view, it is an object of the present invention to provide a device and a method which can display data in an appropriate display area for each processing unit, such as an application, according to the applied equipment.
(1) A display control device and method according to the present invention defines a plurality of display areas in the display device, and when a display area acquisition request is received from each processing unit, it is decided whether to use the requested display area, and the processing unit which is allowed to use the display area can display data there. By defining display areas in advance, and by allowing the use of each display area, without leaving control to each processing unit, an appropriate display for each processing unit according to the applied equipment becomes possible. Also inappropriate display is prevented.
(2) When display area acquisition requests are received from a plurality of processing units, the display control device according to the present invention judges whether the display areas subject to respective acquisition requests can coexist, and if the plurality of processing units are requesting acquisition of display areas which cannot coexist, use is allowed to one of the processing units. As a consequence, a plurality of display processing which cannot coexist can be prevented and appropriate display becomes possible.
(3) When the display areas subject to respective acquisition requests all or partially overlap, the display control device according to the present invention judges as coexistence impossible. As a consequence, it is possible to control such that displays by a plurality of processing units do not overlap.
(4) When a plurality of processing units request acquisition of one display area, the display control device according to the present invention judges as coexistence impossible. As a consequence, it is possible to control such that two or more processing units are not allowed to use one display area.
(5) When a plurality of display areas subject to respective acquisition requests partially overlap, the display control device according to the present invention judges as coexistence possible. As a consequence, it is possible to control such that a partial overlapping display is allowed.
(6) When a display processing is executed for a plurality of display areas which can coexist with partial overlapping portions, the display control device in accordance with the present invention displays assigning priority to an area having a higher priority in the overlapped portion. As a consequence, it is possible to control such that the overlapped portion is displayed according to priority.
(7) The display control device in accordance with the present invention judges the possibility of coexistence based on the coexistence relationship information where the possibility of coexistence of a plurality of display areas has been defined in advance. As a consequence, it is possible to quickly judge whether the requested display areas can coexist.
(8) When an acquisition request for a display area which cannot coexist is received, the display control device in accordance with the present invention allows use to the processing unit which sent the request first. As a consequence, it is possible to assign priority to the display by the processing unit which sent the display request first.
(9) When an acquisition request for a display area which cannot coexist is received, the display control device in accordance with the present invention allows use to the processing unit which has the higher priority. As a consequence, it is possible to display data which is most urgent, such as a warning display.
(10) When an acquisition request for a display area which cannot coexist is received, the display control device in accordance with the present invention allows use to the processing unit which requests the area having the highest priority. As a consequence, areas in a display can be different depending on the urgency.
(11)-(14) The display control device according to the present invention stores a processing unit which requested acquisition but was not allowed use of the display area as an acquisition waiting, and allows use of the display area when allowance is possible. As a consequence, use is allowed sequentially for display area acquisition requests. Each processing unit does not have to request acquisition again. If use is allowed considering the order of received requests, priority given to the processing units, and priority given to the display areas, then use can be allowed according to sequence in the order considering such priorities.
(15) When a request for a display area which cannot coexist is received, the display control device according to the present invention changes the display area requested by one or more processing units so as to allow use as a plurality of display areas which can coexist. As a consequence, a plurality of displays can coexist as much as possible while maintaining an appropriate display by a plurality of display areas.
(16) When a request for a display area which cannot coexist is received, the display control device according to the present invention changes the display area based on dependency relationship information defining the changes of the display area to make coexistence possible. As a consequence, the display area can be quickly changed so as to make coexistence possible.
(17)(21) The display control device according to the present invention defines the processing units which are allowed use for each display area as acquisition right information, and when a display area acquisition request is received from each processing unit, the display control device refers to the acquisition right information and decides whether use of the display area is allowed for each processing unit. As a consequence, it is possible to control by allocating processing units for each display area.
(18) The display control device according to the present invention does not allow two or more processing units simultaneous use of one display area. As a consequence, it is possible to control so as to correlate a display area and a processing unit on a one-to-one basis.
(19)(20) The display control device according to the present invention allows two or more processing units simultaneous use of one display area. As a consequence, it is possible to control so as to allow two or more processing units to use one display area.
(22)(23) When the processing unit which requested the display area is actually not in a state to display on the display area, or is not in a state to execute processing related to the display processing, the display control device according to the present invention does not allow the processing unit to use the display area even if the display area requested by the processing unit can coexist with display areas requested by other processing units. As a consequence, to make display efficient, use is not allowed for a processing unit which cannot actually execute display processing and processing related to display.
(24) The display control device according to the present invention also has display processing supervisory means, wherein when each processing unit executes display processing for each display area, it is supervised whether the display processing is by a processing unit which is allowed use of the display area. As a consequence, execution of invalid display processing can be supervised.
(25)(26) The display control device according to the present invention assigns a key to the processing unit when use of a display area is allowed, and the display processing supervisory means supervises by judging whether the key shown by the processing unit is the correct key. As a consequence, invalid display processing can be easily supervised. By assigning a different key each time, invalid display processing using an old key can be prevented.
(27) When a processing unit attempted to execute display processing for a display area which is not allowed use is discovered, the display control device according to the present invention executes processing to disable the display processing by the processing unit. As a consequence, a processing unit which attempted invalid display processing can be removed.
In the present invention, xe2x80x9cprocessing unitxe2x80x9d refers to a set of processings to obtain a certain result. One processing unit may be comprised of one task, but may include two or more tasks.
The concept xe2x80x9ccase when all the display areas subject to the acquisition requests overlapxe2x80x9d includes the case when two or more acquisition requests are received for the same display area.
xe2x80x9cCannot coexistxe2x80x9d is the case when displaying in a plurality of display areas is not desirable. Depending on the equipment to which the display control device is applied to or depending on the status, a plurality of display areas may not be able to coexist if a part of the display area overlaps, or may be able to coexist even if overlapping exists in a predetermined allowable range. There is also a case when a specific display area can coexist even if it overlaps with another display area.
The concept xe2x80x9cresource used by a processing unitxe2x80x9d0 includes not only hardware but also software, such as data and programs.
The concept xe2x80x9cdisplay area storage meansxe2x80x9d means for storing the definitions of display areas, and includes means for substantially defining display areas, regardless table format or descriptions in a program. In the embodiments, the display area definition table in FIG. 6 falls under this concept.
The concept xe2x80x9cdisplay area management meansxe2x80x9d refers to a means for deciding whether use of the area is allowed at least when a display area acquisition request is received. In the embodiments, the display control program shown in e.g. FIG. 8 falls under this concept.
The concept xe2x80x9ccomputerxe2x80x9d refers to a device which executes processing according to a program, and includes a personal computer, and a CPU and MPU built-in to such equipment as a TV.
xe2x80x9cRecording medium where a program is recordedxe2x80x9d is such a recording medium as ROM, RAM, a flexible disk, CD-ROM, memory card and hard disk, where a program is recorded. This concept includes not only such a recording medium as a hard disk which is connected to a CPU and with which the recorded program is directly executed, but also such a recording medium as CD-ROM which records a program to be executed after installing it on a hard disk. A program here includes not only a program which can be directly executed, but also a source format program, compressed program and enciphered program.